handling empty credentials during unbinding

[jayeshjk]

• For the bosh operator, there is no need to forward request to service agent if the credentials for binding don't exist. This can happen during the unbind request of the previously failed binding. (Orphan mitigation)

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this:

https://www.pivotaltracker.com/story/show/178266004

The labels on this github issue will be updated when the story is started.

[coveralls]

Pull Request Test Coverage Report for Build 5413

• 4 of 5 (80.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.01%) to 88.816%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
broker/core/provisioner-services/src/DirectorService.js	4	5	80.0%

Totals
Change from base Build 5407:	0.01%
Covered Lines:	9693
Relevant Lines:	10537

---

💛 - Coveralls

[codecov]

Codecov Report

Merging #1323 (fc58a61) into master (0b67b98) will decrease coverage by 0.39%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1323      +/-   ##
==========================================
- Coverage   72.16%   71.77%   -0.40%     
==========================================
  Files          44       44              
  Lines        3837     3837              
==========================================
- Hits         2769     2754      -15     
- Misses        754      766      +12     
- Partials      314      317       +3